<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div,#b,.c{
            font-size: 2em;
            font-weight: bold;
        }
    </style>
</head>
<body>
<div>aaaaa</div>
<p id="b">bbbb</p>
<h1 class="c">cccc</h1>
</body>
</html>